The present invention relates to a self propelled apparatus for digging a shallow trench along one side of an existing roadway, and which is useful as part of a roadway widening operation.
Roadway planing machines are known which are adapted for removing the surface of the roadway and conveying the removed material to the bed of an adjacent truck. Such planing machines typically include a rotatable cutter drum having a plurality of teeth mounted on its surface and which is adapted for removing a thickness of the asphalt paving, note for example U.S. Pat. Nos. 5,078,540; 4,193,636; and 4,139,318. While these prior planing machines are suitable for their intended purpose, they are not capable of digging a trench along the side of an existing roadway as part of a roadway widening operation, since in most cases the central location of the cutter drum renders it impossible to align the drum along the side of the roadway by reason of inadequate room along the shoulders of the roadway. In addition, most widening trenches are more narrow and deeper than the cutter drums are capable of digging.
It is accordingly an object of the present invention to provide a roadway trenching apparatus which is capable of effectively and efficiently digging a trench along the side of an existing roadway, and removing the soil or other material from the trench and delivering the same to the bed of an accompanying truck or placing the material at the side of the newly cut trench.
It is also an object of the present invention to provide a roadway trenching apparatus which forms a trench with a square edge along the side of an existing roadway, so as to provide a square joint between the existing roadway and new roadway extension.
It is a further object of the present invention to provide a roadway trenching apparatus which is capable of being readily modified to provide a trench of any one of several selected widths.
It is still another object of the present invention to provide a roadway trenching apparatus which is capable of providing a selected depth in the trench being formed, and which has provision for elevation and grade control of the trench.